Concede needs a punishment.

No ifs or buts. You should not que yourself into a game unless you are willing to actually play.

Every time that a person concedes they should have a time ban before they can enter into another game.

Either do that, or make it so they have to sacrifice a certain amount of the in-game currency to be able to do it. Lets put it at 100 for an example.

There is absolutely no reason at all why there should ever be an option to freely leave the game at any given moment once you've already qued yourself into a match. Simply don't que yourself in to play then.

*I am done replying to people in this post, I get it, everyone loves conceding. Lets see how that works out for you in real world applications. There won't be a concede button for you everywhere. The only thing I can do is wait and see if they ever apply a much needed punishment to the function. I do agree that we need to be able to use it at times, due to glitches or other weird mishaps.. but in NO WAY should it ever be used in normal play, or when you're about to lose, or feel you can't win. Relish in your loss, you're the one who made the deck to make you lose.